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Biomedical subjects

C Bureau

Publications and source records attributed to C Bureau.

15 recordsLinked to original sources
PubMed2006

Treatment of experimental murine pancreatic peritoneal carcinomatosis with fibroblasts genetically modified to express IL12: a role for peritoneal innate immunity.

BACKGROUND: Peritoneal carcinomatosis from pancreatic cancer has a poor prognosis with a median survival of 3.1 months. This is mainly due to lack of effective treatment. Interleukin 12 (IL12) is a proinflammatory cytokine that has a potent antitumoral effect by stimulating innate and adoptive immunity. AIM: To examine the antitumoral effect and toxicity of intraperitoneal delivery of IL12 using an ex vivo gene therapy approach in a murine model of pancreatic peritoneal carcinomatosis. METHODS: Peritoneal carcinomatosis was generated by direct intraperitoneal inoculation of the pancreatic cancer cell line Capan-1 in athymic mice. Syngenic fibroblasts were genetically modified in vitro to secrete IL12 using a polycistronic TFG murine IL12 retroviral vector coding for both p35 and p40 murine IL12 subunits. Ex vivo gene therapy involved injection of the genetically modified fibroblasts intraperitoneally twice a week for 4 weeks. RESULTS: Treatment of pre-established peritoneal carcinomatosis with fibroblasts genetically modified to express IL12 induced a marked inhibition of tumour growth as measured by comparison of the weights of the intraperitoneal tumour nodules in the treated and control animals (3.52 (SD 0.47) v 0.93 (SD 0.21) g, p<0.05) and improved survival. This effect was associated with infiltration of the peritoneal tumour nodules with macrophages. Peritoneal lavage confirmed enhancement of the innate peritoneal inflammatory activity, with an increased number of activated macrophages and natural killer cells. Moreover, macrophages harvested from animals with peritoneal carcinomatosis and treated with IL12-expressing fibroblasts expressed an activated proinflammatory antitumoral M1 phenotype that included strongly enhanced reactive oxygen species and nitric oxide production. There was no treatment-related toxicity. CONCLUSION: Multiple injections of genetically modified fibroblasts to express IL12 is an effective and well-tolerated treatment for experimental murine pancreatic peritoneal carcinomatosis via activated innate immunity and in particular activated M1 macrophages.

Animals↗
PubMed2005

Leachate pre-treatment strategies before recirculation in landfill bioreactors.

Nitrified leachate recirculation represents a promising strategy for a more sustainable landfill management. Our objective was to determine the reactions involved in nitrate reduction in municipal solid waste batch biodegradation tests. Anaerobic digestion of waste in the three control reactors showed a good reproducibility. In two test reactors, nitrate was added at various moments of the waste degradation process. We observed that: (1) H2S concentration controlled the nitrate reduction pathway: above a certain threshold of H2S, dissimilatory nitrate reduction to ammonium (DNRA) replaced denitrification. (2) N2O/N2 ratio varied with the organic carbon concentration: the lower the easily biodegradable carbon concentration, the higher the N2O/N2 ratio. (3) N2 was consumed after denitrification. The possibility of a nitrogen fixation reaction in the presence of NH4 is discussed. Nitrified leachate recirculation during acidogenesis should be avoided because of higher H2S production which could induce DNRA.

Bacteria, Anaerobic↗
PubMed2001

Nonstructural 3 protein of hepatitis C virus triggers an oxidative burst in human monocytes via activation of NADPH oxidase.

It has been shown that oxidative stress occurs in chronic hepatitis C. Release of reactive oxygen species (ROS) from sequestered phagocytes and activated resident macrophages represents the predominant component of oxidative stress in the liver. However, little is known about the ability of the monocyte to produce ROS in response to protein of hepatitis C virus. In this study, we investigated the ROS production in human monocytes stimulated by several viral proteins of hepatitis C virus. Human monocytes from healthy blood donors were incubated with recombinant viral protein: Core, NS3, NS4, and NS5. ROS production was measured by chemiluminescence. Only NS3 triggered ROS production in human monocytes. Generated ROS were mainly the anion superoxide. NS3 also induced a rapid and transient increase in intracellular calcium concentration measured by a video digital microscopy technique. By using different metabolic inhibitors, we showed that ROS production requires calcium influx, tyrosine kinases, and the stress-activated protein kinase, p38. The study of p47(PHOX) phosphorylation and translocation showed that NADPH oxidase was activated and involved in ROS production induced by NS3. In a second experiment, NS3 inhibited the oxidative burst induced by phorbol 12-myristate 13-acetate. These results indicate that NS3 activates NADPH oxidase and modulates ROS production, which may be involved in the natural history of hepatitis C infection.

Calcium↗
PubMed2001

Maintenance therapy with gradual reduction of the interferon dose over one year improves histological response in patients with chronic hepatitis C with biochemical response: results of a randomized trial.

BACKGROUND/AIMS: Our aim was to assess whether histological response was improved by continuing interferon-alpha (IFN) treatment in patients with chronic hepatitis C (HCV) with a biochemical response and no viral clearance after a usual IFN treatment. METHODS: Fifty-seven patients with normal alanine aminotransferase (ALAT) levels and positive HCV RNA at the end of a 1 year IFN treatment were randomly assigned to either group 1 (n = 28) where IFN was stopped, or group 2 (n = 29) where IFN was continued for 1 more year with gradual reduction of the dose to keep serum ALAT activity below the upper limit of normal. Liver biopsies were obtained before, and then 6 months after the end of treatment. RESULTS: Knodell's index improved between paired biopsies in group 2 (8.2+/-2.4 vs. 5.5+/-2.1), but not in group 1 (8+/-2.3 vs. 6.5+/-2). In post-treatment biopsies, the METAVIR activity score was significantly lower in group 2 than in group 1 (0.7+/-0.2 vs. 1.1+/-0.3, P < 0.05). In group 2, an improvement of the METAVIR fibrosis score was observed (1.3+/-0.4 vs. 1.1+/-0.2), whereas fibrosis progressed in group 1 (1.3+/-0.4 vs. 1.6+/-0.4). CONCLUSIONS: Maintenance therapy by the minimal dose of IFN able to maintain biochemical response prevents histological progression in the sub-group of patients without virological response.

Adult↗
PubMed2000

Study of host- and virus-related factors associated with spontaneous hepatitis C virus clearance.

Epidemiologic parameters, virologic characteristics and frequency of HLA class II DR and DQ antigens were compared between 63 subjects with spontaneous hepatitis C virus clearance (group 1) and 282 patients with chronic active hepatitis C virus infection (group 2). DRB1*1101 and moreover DQB1*0301 alleles were more frequent in group 1 than in group 2 (33.8% vs. 14.7% and 64.4% vs. 28.6%; P=0.012 and P=0.003, respectively). The frequency of DQB1*02 was lower in group 1 than in group 2 (25.4% vs. 49%; P=0.04). No difference was observed in viral genotype distribution between group 1 and group 2. Univariate analysis showed that female sex and contamination by intravenous drug use were associated with self limited infection. However, by multivariate analysis, the only independent factor associated with hepatitis C virus RNA clearance was female sex (P=0.004). In conclusion, spontaneous hepatitis C virus RNA clearance is determined by class II antigens (mainly DQB1*0301) and female sex, while viral genotype plays no role.

Adult↗
PubMed1996

Transmission of hepatitis C virus in allografted patients: use of viral genotyping as an epidemiological marker.

One hundred and ninety-two allografted patients were tested for hepatitis C virus (HCV) RNA from 1992 to 1995 in Saint-Louis Hospital (Paris). They received blood products and intravenous immunoglobulins (IVIG) and more particularly Gammagard IVIG suspected of transmitting HCV (batches distributed in France between January 1993 and February 1994). The presence of serum HCV RNA was tested by polymerase chain reaction (PCR) in 86 patients who received Gammagard IVIG during the critical period and in 106 patients treated with IVIG other than the suspected batches of Gammagard (negative controls). HCV RNA positive sera were HCV genotyped. Ten out of 86 patients who received Gammagard IVIG during the exposed period vs 0 out of 106 negative controls were HCV RNA positive showing a higher prevalence of HCV infection in the exposed patients that in the negative controls (P = 0.001). The link between HCV transmission and IVIG infusion was reinforced by the high frequency of genotype 2b (70%) in the exposed patients because genotype 2b is an underrepresented subtype in France (< 1%).

Biomarkers↗
PubMed1994

Melatonin is able to influence its secretion in humans: description of a phase-response curve.

A single physiological dose of melatonin (20 micrograms for 3 h given intravenously at different times of the day (04.00-12.00, 16.00 and 20.00 h) was able to shift the endogenous plasma melatonin profile of healthy volunteers under entrained conditions according to a phase-response curve (PRC). ANOVA showed an effect of the time of administration on the onset, the acrophase or the offset of the melatonin profiles. These profiles were significantly delayed when the infusion was administered at 12.00 h and advanced when the infusion was given at 20.00 h. Further, the AUCs evaluated on the nocturnal melatonin profiles were increased after the 04.00 h infusion (+20.5%, p < 0.05), whereas they were decreased after the 12.00 h infusion (-20%, p < 0.05). Lastly, no alteration was observed for cortisol rhythm, whatever the time of melatonin administration. These results, which show that according to a PRC the system regulating melatonin secretion is sensitive to a single short-term administration of the hormone given at a low dose, support the paradigm of the endogenous synchronizer melatonin.

Adult↗
PubMedDate not supplied

[Non-parametric estimation of pharmacokinetic parameters of amikacin in patients with non-insulin-dependent diabetes mellitus].

To establish a reference for MAP Bayesian adaptive control of amikacin therapy in non-insulin-dependent diabetic patients, 30 patients (age: 63.5 +/- 10.1 years) were studied. Weight (84.2 +/- 15.4 kg) and body mass index (28.0 +/- 4.3 kg/m2 for males and 30.5 +/- 6.4 kg/m2 for females) were stable during treatment. Creatinine clearance (CCr) was 70.3 +/- 27.2 ml/min/1.73 m2 before treatment and 69.6 +/- 24.3 ml/min/1.73 m2 (NS) at the end of treatment (2 to 15 days). 129 serum concentrations were drawn (4.8 +/- 2.6 levels per patient). The one-compartment model was parameterized as having Vs (l.kg-1) and Kslope (min/ml.h) for each unit of CCr (Kel = Kintercept + Kslope x CCr). The non-renal Kintercept was fixed at 0.00693 h-1. The NPEM computes the joint probability densities. The mean, median, and SD were respectively: Vs = 0.3574, 0.3654, 0.0825 l.kg-1; Kslope = 0.0026, 0.0027, 0.0007 min/ml.h. For the a priori first doses determination, precision is higher with the new population. No difference in adaptive control was observed. In additive, the full joint density probability should be used to develop stochastic multiple model linear quadratic (MMLQ) adaptive control strategies.

Amikacin↗